[jira] [Closed] (TEXT-130) JaroWinklerDistance: Wrong results due to precision of transpositions

["Pascal Schumacher (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/TEXT-130?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Pascal Schumacher closed TEXT-130.
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       Resolution: Fixed
    Fix Version/s: 1.5

> JaroWinklerDistance: Wrong results due to precision of transpositions
> ---------------------------------------------------------------------
>
>                 Key: TEXT-130
>                 URL: https://issues.apache.org/jira/browse/TEXT-130
>             Project: Commons Text
>          Issue Type: Bug
>    Affects Versions: 1.4
>            Reporter: Jan Martin Keil
>            Assignee: Rob Tompkins
>            Priority: Major
>             Fix For: 1.5
>
>
> The method {{JaroWinklerDistance#matches}} returns {{transpositions / 2}} as integer. However, it is not granted for {{transpositions}} to be even. E.g. comparing "aaabcd" and "aaacdb" will result in {{transpositions}} = 3. Therefore the method must return 1.5, not 1. Otherwise the similarity is 0.9611111111111111 instead of 0.9416666666666667.
> I recommend to return {{halfTranspositions}} instead of {{transpositions}} and doing the cast and division ({{(double) mtp[1] / 2}}) in {{JaroWinklerDistance#apply}}.



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